The invention relates to kites used for both traction and non-traction purposes, and for both recreational and non-recreational purposes. In particular, this invention describes a control line assembly for kites of the type that maintain a deeply arched shape while flying, and which attach to the primary control means at two points on each end of the kite. Kites of this type can take any of several forms: inflatable kites, ram air foil kites, and kites with rigid or semi-rigid spars, or a combination of air-type bladders and ram air inflation.
While the use of kites to deliver tractive force to vehicles is not a new concept, recent developments in the field of traction kiting has increased interest in kites that are useful for a variety of applications such as recreation, auxiliary power for watercraft, and even as tractive power for life rafts and sailors adrift at sea. These developments have also increased interest in kites that are not used for traction purposes but which are suitable for training potential users of traction kites.
Kites suitable for these applications are usually of the deeply arched, four-attachment-point type. They have strong anhedral when viewed from in front or behind and typically include a total of four primary attachment points for control lines, two points at each end of the kite. They can further be categorized as two line or four-line, depending on the number of control lines used to fly them.
Traditionally, two-line kites of this general type have pointed ends. These pointed ends are connected to the two control lines by means of two primary bridle lines that are situated so as to take most of the flying loads generated by the kite. Four additional bridle lines attach to the kite, or slide through line guides that are attached to the kite, and serve to provide the kite with steering capabilities. Users can make slight adjustments to kite power and steering quickness by adjusting the lengths of these lightly-loaded bridle lines. The kite control lines are also attached to a control device, usually a bar.
All kites of this type will steer from side to side when the user pulls alternately on one kite line then the other. For example, if a user wants to turn a kite to his or her left, he or she pulls on the left-hand control line, or left-hand side of the control bar. A benefit of two-line kites is slow steering, for those that want slow steering. This is a useful feature for both novices and some expert users.
All kites of this type can also be leashed to the user in a manner that permits the kite to remain attached to the user when the user releases the control bar. For safety reasons, it is necessary that the kite be leashed to the user in such a way that the kite de-powers when the control bar is released. An advantage of a two-line kite over a four-line kite is that the control lines of the two-line kite are less likely to tangle when the user releases the control bar. This is particularly useful for novice users.
Four line kites of the type being discussed here generally have truncated ends, as opposed to the pointed ends of two-line kites, and they typically have no bridle lines. The four kite control lines attach directly to the four primary attachment points on the ends of the kite. The control lines are usually attached to a control bar, and the user steers a four-line kite in precisely the same way as he or she steers a two-line kite. Pull on the left side of the bar and the kite steers to the left.
Four-line kites of this type can be trimmed to the wind in such a way that the force produced can be increased or decreased. Shortening the two control lines that are attached to the front of the kite reduces the kite""s angle of attack to the wind and causes a reduction in force generated by the kite. Lengthening those lines increases the kite""s angle of attack, thus increasing the force generated. There is a limit on the force increase generated, however, as over-lengthening of the front lines will cause some four-line kites to stall.
Heretofore, kite owners had to decide whether they wanted a two-line kite, with its slower steering and lower likelihood of line entanglement, or a four-line kite with its quicker steering and on-the-fly angle of attack adjustment. An owner of a two-line kite who wanted a quicker steering kite and the ability to adjust the angle of attack on-the-fly could convert it to a four line kite by rolling up and sewing the pointed end and thereby creating a truncated end for four-line attachment. Two-line kites have two primary attachment points at each end plus at least one, usually two, line guides at each end, an and entirely different and additional set of attachment points for use when in a kite is converted for flying with four lines. This results in a redundancy of hardware attached to the kites, and these kites are more costly and complex than they need to be.
Owners of arched type four-attachment-point kites did not have the option of converting their kites to kites with two-line control, in that all attempts to do so prior to the invention disclosed herein were not successful.
In the prior art, various devices are known to provide wind power to drive sailboards and the like. For example, U.S. Pat. No. 4,708,078 issued to Legaignoux et al. discloses a kite controlled by a single line attached to each end of a wing in the form of a spherical segment. French patents issued to Legaignoux et al., U.S. Pat. Nos. 2,762,583 and 2,698,847, each show inflatable kites with four control lines, two attached to each end of the kite, but do not disclose a way to convert those kites to kites controlled by two lines.
Additionally, U.S. Pat. No. 5,366,182 issued to Roeseler et al shows an airfoil used to provide tractive force for pulling water skis and the like. One embodiment of the Roeseler Patent discloses the use of bridle lines for connecting the airfoil to the conveyance device being pulled, but these bridle lines do not work with arch-type kites, they do not impart the ability to steer the kite, nor do they offer the ability to de-power the kite.
Thus, there is a need for a control assembly that would allow four line-kites to be A converted to two-line controlled kites. A need further exists for such assemblies that would eliminate the need for redundant hardware on two-line kites, thereby reducing the cost and complexity of these kites. There is also a need for such assemblies that will allow a user to rapidly de-power a kite.
Accordingly, the following are objects of this invention:
1. to provide efficient control assemblies that will allow four-line arch-type kites to be converted to kites controlled by two lines;
2. to provide efficient control assemblies that will allow kites thus converted to be effectively steered;
3. to provide efficient control assemblies that will allow a user to avoid injury or equipment damage by rapidly de powering a kite;
4. to provide efficient control assemblies that reduce the time required to prepare the kite for use or storage;
5. to provide efficient control assemblies with the capability to stow the line when the kite is not in use;
6. to provide such assemblies in affordable, cost-effective forms; and
7. eliminate the need for redundant hardware currently found on most two-line kites. These and such other objects of the invention, as will become evident from the disclosure below, are met by the invention disclosed herein.
The double-up converter allows arch-type kites with truncated tips and four line attachment points to be flown with two lines. It can take a number of forms; some with lines only, and others with lines and two roughly triangular fabric panels, the panels having connectors to attach to the truncated ends of the kite.
The invention provides efficient control for deeply arched, four-attachment-point kites by using control line assemblies consisting of control lines, bridle lines, and cross-bridle lines. All embodiments provide line guides and line stops for rapidly de-powering a kite. In a number of embodiments, the length of various bridle lines are changeable.
According to the teachings of this invention, the control assemblies may be attached to each end of the kite by means of; knots, adjustable straps such as strap-and-buckle, or lines, such as adjustable shock cord arrangements. Additionally connections of bridle lines to control lines, bridle lines to bridle lines, and bridle lines to rings are made by means of; knots, such as lark""s head knots or other knots that would be obvious to one skilled in the art.
The operator or assembler may adjust the performance of the kite by selectively changing the length of various bridle lines on the control assemblies or by changing the length of the cross-bridle lines. For example, if a less powerful kite is desired, angle of attack might be decreased by shortening the front primary bridle lines or triangle bridle lines; a more powerful kite might be obtained by lengthening the front primary bridle lines or triangle bridle lines. In another example, a user can decrease the turning radius of a kite by shortening the cross-bridle lines. The bridle line and cross-bridle line adjustments are accomplished by means of; buckles or other adjustment devices that would be obvious to one skilled in the art.
In an alternative embodiment, a pair of roughly triangular panels of fabric replace the triangle bridle lines, of the line-only version of the control assembly. These removable panels can be used to change the angle of attack, and they can include pouches for organizing and storing bridle lines.
The control assemblies described in this invention are equally adaptable for use on all kites with four line attachment points. These embodiments, and other embodiments described below, allow four-line kites to be converted to kites controlled by two lines. These embodiments and other embodiments described below, also allow a kite to be prepared for use or storage in a minimum amount of time relative to conventional four-line kites. All of these embodiments, and other embodiments described below, also allow a user to rapidly de-power a kite while it is in use.